Cycloalkylidene dyes

ABSTRACT

Cycloalkylidene dyes have the formula ##STR1## where m is 0 or 1, 
     L is a chemical bond or C 1  -C 2  -alkylene, which may be substituted, 
     R 1  is hydrogen, C 1  -C 20  -alkyl, which may be phenyl-substituted, substituted or unsubstituted phenyl, naphthyl or C 3  -C 7  -cycloalkyl, 
     Y is oxygen or two hydrogens, 
     X 1  is oxygen and 
     X 2  is C 1  -C 8  -alkanoyloxy, substituted or unsubstituted benzoyloxy, C 1  -C 6  -trialkylsilyloxy or a radical of the formula OR 1  or NR 2  R 3 , where R 1  is as defined above and R 2  and R 3  are identical or different and each is independently of the other C 1  -C 20  -alkyl, which may be phenyl-substituted, substituted or unsubstituted phenyl, naphthyl, or C 3  -C 7  -cycloalkyl or R 2  and R 3  together with the nitrogen atom joining them are saturated heterocyclyl, or else one of R 2  and R 3  is hydrogen, or X 1  and X 2  together are a radical of the formula ##STR2##  where Z is oxygen, sulfur or NR 2 , where R 2  is as defined above, and 
     Q is a carbocyclic or heterocyclic ring in which the substituents N and Z occupy adjacent positions.

The present invention relates to cycloalkylidene dyes of the formula I##STR3## where m is 0 or 1,

L is a chemical bond or C₁ -C₂ C-alkylene, which may be monosubstitutedor disubstituted by C₁ -C₄ -alkyl, R is hydrogen, C₁ -C₂₀ -alkyl, whichmay be phenyl-substituted, substituted or unsubstituted phenyl, naphthylor C₃ -C₇ -cycloalkyl,

Y is oxygen or two hydrogens,

X¹ is oxygen and

X² is C₁ -C₈ -alkanoyloxy, substituted or unsubstituted benzoyloxy, C₁-C₆ -trialkylsilyloxy or a radical of the formula OR or NR² R³, where R¹is as defined above and R² and R³ are identical or different and each isindependently of the other C₁ -C₂₀ -alkyl, which may bephenyl-substituted, substituted or unsubstituted phenyl, naphthyl, or C₃-C₇ -cycloalkyl or R² and R³ together with the nitrogen atom joiningthem are 5- or 6-membered saturated heterocyclyl which may containfurther hetero atoms, or else one of R² and R³ is hydrogen, or X¹ and X²together are a radical of the formula ##STR4## where Z is oxygen, sulfuror N², where R² is as defined above, and

Q is a 5- or 6-membered saturated or aromatic, carbocyclic orheterocyclic ring in which the substituents N and Z occupy adjacentpositions.

Helv. Chim. Acta 64 (1981), 2665-80, discloses compounds derived fromquinoxaline and doubled via the heterocyclic ring.

It is an object of the present invention to provide new cycloalkylidenedyes which should be simple to prepare and have advantageous applicationproperties.

We have found that this object is achieved by the cycloalkylidene dyesof the formula I defined at the beginning.

Any alkyl appearing in the abovementioned formula I may be eitherstraight-chain or branched.

Any substituted phenyl appearing in the abovementioned formula I mayhave as substituents for example C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy orhalogen.

L is for example methylene, ethylene, ethylidene, 1-propylidene,2-propylidene, 1,2-propylene, 1,2-butylene, 2,3-butylene, 3-pentylideneor 3,4-hexylene.

R¹, R² and R³ are each for example methyl, ethyl, propyl, isoproyl,butyl, isobutyl, sec-butyl, pentyl, isopentyl, neopentyl, tert-pentyl,hexyl, 2-methylpentyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl,undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl,heptadecyl, octadecyl, nonadecyl, eicosyl, benzyl, 1- or 2-phenylethyl,phenyl, 2-, 3- or 4-methylphenyl, 2,4-dimethylphenyl, 2-, 3- or4-methoxyphenyl, 2,4-dimethoxyphenyl, 2-, 3- or 4-chlorophenyl,2,6-dichlorophenyl, 2-, 3- or 4-bromophenyl, 1-naphthyl, 2-naphthyl,cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl.

Any 5- or 6-membered saturated heterocyclyl formed by R² and R³ togetherwith the nitrogen atom joining them together can be for examplepyrrolidino, piperidino, morpholino, piperazino or N-(C₁ -C₄-alkyl)piperazino.

X² is for example formyloxy, acetyloxy, propionyloxy, butyryloxy,isobutyryloxy, pentanoyloxy, hexanoyloxy, heptanoyloxy, octanoyloxy,2-ethylhexanoyloxy, benzoyloxy, 2-methylbenzoyloxy, 2-methoxybenzoyloxy,2-chlorobenzoyloxy, trimethylsilyloxy, triethylsilyloxy,tripropylsilyloxy, triisopropylsilyloxy, tributylsilyloxy,tripentylsilyloxy or trihexylsilyloxy.

When X¹ and X² are combined to form a radical of the formula ##STR5## itcan be for example ##STR6## which ring systems may each additionally bemonosubstituted or polysubstituted by C₁ -C₁₀ -alkyl, C₁ -C₁₀ -alkoxy,nitro, amino, C₁ -C₄ -monoalkylamino, C₁ -C₄ -dialkylamino, pyrrolidino,piperidino, morpholino, piperazino, N-(C₁ -C₄ -alkyl)piperazino orhalogen.

Preference is given to cycloalkylidene dyes of the formula I where L isa chemical bond or 2-propylidene.

Particular preference is given to cycloalkylidene dyes of the formula II##STR7## where R¹ is hydrogen, C₁ -C₁₀ -alkyl, which may bephenyl-substituted, phenyl or naphthyl, and

X² is as defined above.

Particular preference is further given to cycloalkylidene dyes of theformula III ##STR8## where n is 1, 2, 3 or 4,

R¹ is hydrogen, C₁ -C₁₀ -alkyl, which may be phenyl-substituted, phenylor naphthyl,

R⁴ is C₁ -C₁₀ -alkyl, C₁ -C₁₀ -alkoxy, nitro, amino, C₁ -C₄-monoalkylamino, C₁ -C₄ -dialkylamino, pyrrolidino, piperidino,morpholino, piperazino, N-(C₁ -C₄ -alkyl)piperazino, or halogen, and

Z is as defined above.

Very particular preference is given to cycloalkylidene dyes of formulaI, II or III where R¹ is hydrogen and, in the formula I, m is 0.

Very particular preference is further given to cycloalkylidene dyes ofthe formula I or II where X² is hydroxyl, C₁ -C₈ -alkoxy, C₂ -C₄-alkanoyloxy, benzoyloxy, trimethylsilyloxy, C₁ -C₈ -monoalkylamino,cyclopropylamino, cyclopentylamino, cyclohexylamino, benzylamino,phenylethylamino, phenylamino, 2-, 3- or 4-methylphenylamino,1-naphthylamino or 2-naphthylamino.

Very particular preference is further given to cycloalkylidene dyes ofthe formula III where

Z is C₁ -C₈ -alkylimino, cyclopropylimino, cyclopentylimino,cyclohexylimino, benzylimino, phenylethylimino, phenylimino, 2-, 3- or4-methylphenylimino, 1-naphthylimino or 2-naphthylimino.

The novel cycloalkylidene dyes of the formula I can be obtained forexample by treating the methyl compounds of the formula IV ##STR9##where m, L and R¹ are each as defined above, first with aqueous acidswithin the range from 20° C. to the boiling point of the reactionmixture and then, following intermediary isolation, with compounds ofthe formula V

    X.sup.3 --Hal                                              (V)

where

X³ is C₁ -C₈ -alkanoyl, substituted or unsubstituted benzoyl or C₁ -C₆-trialkylsilyl, and

Hal is halogen.

Instead of the carbonyl halides it is also possible to use thecorresponding anhydrides.

Suitable aqueous acids are for example aqueous mineral acids and aqueousorganic acids, such as hydrochloric acid, aqueous sulfuric acid, aqueousp-toluenesulfonic acid, aqueous trifluoroacetic acid, aqueous formicacid or aqueous oxalic acid. The water content of these acids is ingeneral within the range from 5 to 95% by weight.

Following a reaction time which in general varies from 0.5 to 24 hours,the reaction mixture is worked up in a conventional manner (for exampleby filtration, possibly after concentration or dilution of the reactionmixture with water).

The acylation or silylation is carried out in a conventional manner. Theresulting cycloalkylidene dyes I can be purified by crystallization orby means of chromatographic methods.

Those cycloalkylidene dyes of the formula I where X² is NR² R³ can beobtained with advantage by reacting the methyl compound IV with aminesof the formula VI ##STR10## where R² and R³ are each as defined above.

The reaction is advantageously carried out in organic acids, for exampleformic acid, acetic acid, trifluoroacetic acid, p-toluenesulfonic acidor methanesulfonic acid, in the presence or absence of diluents, such aswater, dioxane, tetrahydrofuran or lower alcohols.

The temperature is in general within the range from 20° C. to theboiling point of the reaction mixture.

Methyl compound IV and amine VI are customarily used in a molar ratio offrom 3:1 to 1:3.

Following a reaction time which in general varies from 0.5 to 24 hours,the reaction mixture is worked up as described above.

The dyes according to the present invention act as sensitizers forinitiating photopolymerizations or as sensitizers in electrophotographiccopy layers.

In the presence of oxygen they are capable of forming singlet oxygen onirradiation and therefore they are also suitable for the photodynamictreatment of tumors.

The Examples which follow further illustrate the present invention.

EXAMPLE 1

2,6,6-Trimethylcyclohex-2-ene-1,4-dione

A 1-1 three-neck flask equipped with a gas inlet frit, a stirrer and anintensive condenser was charged with 350 ml of toluene, 350 g ofisophorone, 11.4 g of H₃ [P(Mo₃ O₁₀)₄ ]×H₂ O, 1.4 g of CuSO₄ ·5H₂ O and1.4 g of MoO₃. After compressed air had been passed through at 110° C.for 90 hours, the reaction mixture was added a little at a time at 80°C. into 4 1 of boiling n-hexane. The mixture was then filtered, and thefiltrate was concentrated in a rotary evaporator. The yellowish oilobtained by distillation at 97° C./13 mbar was converted into almostcolorless crystals at -18° C. by addition of 10% by volume of n-hexane.

Yield: 183.8 g (47% of theory).

EXAMPLE 2 3,3,5-Trimethylcyclohex-5-ene-1,2,4-trione

129.4 g of 2,6,6-trimethylcyclohex-2-ene-1,4-dione (from Example 1) wereadded to a solution of 100 g of selenium dioxide in a mixture of 800 mlof dioxane and 50 ml of water, and the mixture was refluxed for 9 hourswith stirring. The precipitate of elemental selenium was then filteredoff with suction, and then all the low boilers were removed in a rotaryevaporator. The residue was distilled at 125° C./20 mbar. The distillatewas melted, mortared with n-hexane and then extracted with 600 ml ofn-hexane. The target product crystallized out in the form of yellowneedles.

Yield: 97.9 g (69% of theory); melting point: 88° C.

EXAMPLE 3Bis(3-hydroxy-5,5-dimethyl-4,6-dioxocyclohex-2-enylidene)ethane

In a 2-1 three-neck flask equipped with an intensive condenser and astirrer, 50 g of 3,3,5-trimethylcyclohex-5-ene-1,2,4-trione (fromExample 2) were dissolved in 300 ml of concentrated hydrochloric acid atroom temperature. The flask was then dipped into a hot oil bath at 100°C. for 15 minutes, in the course of which the reaction mixture turneddark and an orange precipitate formed. This solid precipitate wasfiltered off with suction while hot and washed with water, ethanol,acetone, ethyl acetate and ether. The resulting product was freed ofadhering solvent residues in a desiccator. (It is pure enough in thisstate for further reactions. If desired, it can be recrystallized fromdioxane.)

Yield: 15.5 g (31% of theory), decomposition: 270° C. C₁₈ H₁₈ O₆,M=330.3

Elemental analysis: calculated C 65.45; H 5.49; found C 65.73; H 5.62.

¹ H-NMR₃₀₀ (d₆ -DMSO/TMS): δ=1.29 (s; 12H, Me₂), 7.27, 7.28 (2×s; 2×2H,2-H, α-H), 10.15 (bs; 2H, OH) In addition there are signals of anotherdouble bond isomer.

UV-Vis(dioxane): λ_(max) =440, 421sh, 248 nm

IR (solid, KBr): γ=3360 (OH), 3095 (═C--H), 3030 (═C--H), 2990 (CH₃),2940 (CH₃), 2870 (CH₃), 1675 (C═O), 1652 (C═C═C═O), 1623 cm⁻¹ (C═C).

EXAMPLE 4Bis(3-acetoxy-5,5-dimethyl-4,6-dioxocyclohex-2-enylidene)ethane

2 g of bis(3-hydroxy-5,5-dimethyl-4,6-dioxocyclohex-2-enylidene)ethane(from Example 3) were dissolved in 15 ml of pyridine, and 6 ml of aceticanhydride were added. After stirring for 10 minutes a yellowish greenprecipitate formed, which was filtered off with suction after 1 hour andwashed with ether. The crude product was recrystallized twice fromchloroform, which produced a greenish yellow powder.

Yield: 1.5 g (60% of theory), melting point: 210° C. C₂₂ H₂₂ O₈,M=414.4,

Elemental analysis: calculated C 63.76; H 5.35; found C 63.49; H 5.36.

¹ H-NMR₃₀₀ (CDCl₃ /TMS): δ=1.44 (s; 12H, Me₂), 2.33 (s; 6H, OAc), 7.63(s; 2H, α-H), 7.65 (s; 2H, 2-H)

UV-Vis (CHCl₃): λ_(max) =388, 250 nm

IR (solid, KBr): γ=2980 (═CH), 2935 (CH:), 1765 (COOAc), 1700 (C═O),1675 (C═O), 1180 (C--O--C), 1030 cm⁻¹ (C--O--C)

EXAMPLE 5Bis(3-benzoyloxy-5,5-dimethyl-4,6-dioxocyclohex-2-enylidene)ethane

8 ml of benzoyl chloride were added to a solution of 2 g ofbis(3-hydroxy-5,5-dimethyl-4,6-dioxocyclohex-2-enylidene)ethane (fromExample 3) in 15 ml of pyridine. There was an exothermic reaction, and adirty yellow precipitate formed within 2 hours, which was filtered offwith suction and washed with ether. The crude product was recrystallizedtwice from chloroform, in the form of felted yellow needles.

Yield: 1.1 g (34% of theory), melting point: 224° C. C₃₂ H₂₆ O₈,M=538.55,

Elemental analysis: calculated C 71.3; H 4.8; found C 71.44; H 4.98.

^(1H) -NMR₃₀₀ (CDCl₃ /TMS): δ=1,50 (S; 12H, Me₂), 7.53 (tm; 4H, 3'-H,5'-H), 7.68 (tm; 2H, 4'-H), 7.71 (s; 2H, α-H), 7.83 (s; 2H, 2-H), 8.14(m; 4H, 2'-H, 6'-H)

UV-Vis (CHCl₃) λ_(max) =392, 285, 277 nm

IR (solid, KBr): γ=2980 (CH₃), 1735 (COOBz), 1695 (C═O), 1665 (C═O),1250 (C--O--C), 1055 cm. (C--O--C)

EXAMPLE 6Bis(3-methoxy-5,5-dimethyl-4,6-dioxocyclohex-2-enylidene)ethane

4 g of bis(3-hydroxy-5,5-dimethyl-4,6-dioxocyclohex-2-enylidene)ethane(from Example 3) were dissolved in a mixture of 240 ml of dioxane and240 ml of acetonitrile by refluxing under nitrogen. 16 g of dimethylsulfate were then added, followed by 12 g of finely crushed anhydrouspotassium carbonate. The batch turned greenish blue at once, but becameyellow in the course of an hour of heating under reflux. The reactionmixture was filtered while still hot, the filter cake was washed withacetonitrile, and the combined organic phases were concentrated in arotary evaporator. The residues of alkylating agent were removed bydigestion with ether, and the insolubles were removed by heating inchloroform. The filtrate was concentrated and the residue was repeatedlyrecrystallized from acetone. This gave a solid in the form of reddishyellow prisms.

Yield: 1.4 g (32% of theory), melting point: 247° C. C₂₀ H₂₂ O₆, M=358.4

Elemental analysis: calculated C 67.03; H 6.19; found C 66.74; H 5.91.

¹ H-NMR₃₀₀ (CD₂ Cl₂ /TMS) δ=1.38 (s; Me₂), 3.90 (s: 6H, OMe), 7.05, 7.48(2×s; 2×2H, 2-H, α-H)

UV-Vis (CHCl₃) λ_(max) =433, 240 nm

IR (solid, KBr): γ=3060 (═CH), 2960 (CH₃), 2930 (CH₃), 2835 (OCH₃), 1690(C═O), 1665 (C═O), 1595 (C═C), 1220 (═C--O--C), 1050 cm⁻¹ (═C--O--C)

EXAMPLE 7Bis(5,5-dimethyl-3-trimethylsiloxy-4,6-dioxocyclohex-2-enylidene)ethane

A suspension of 1 g ofbis(3-hydroxy-5,5-dimethyl-4,6-dioxocyclohex-2-enylidene)ethane (fromExample 3) in 50 ml of absolute ethyl acetate was refluxed with 10 ml ofhexamethyldisilazane [(Me₃ Si)₂ NH] with the exclusion of moisture.After heating for 40 minutes a solution formed, and the solvents weredistilled off under an aspirator with interposition of a KOH-filleddrying tower.

As soon as the crude product formed a crystalline precipitate in theheat, it was filtered off with suction through a hot frit and washedwith plenty of cold n-hexane. Crystallization from 10 ml of absoluten-hexane per 0.1 g of crude product in the deep freeze produced thetitle product in the form of reddish orange crystals.

Yield: 1.1 g (74% of theory), decomposition: 170° C. C₂₄ H₃₄ O₆ Si₂,M=474.7

Elemental analysis: calculated C 60.73; H 7.22; found C 60.49; H 7.30.

¹ H-NMR₃₀₀ (CDCl₃ /TMS): δ=0.30 (s; 24H, Me₃ Si), 1.40 (s; 12H, Me₂),7.33 (s; 2H, 2-H), 7.42 (s; 2H, α-H)

In addition there are signals of another double bond isomer.

UV-Vis (dioxane): λ_(max) =440, 420 sh nm

IR (solution, CCl₄): γ=2950 (CH₃), 1685 (C═O), 1665 (C═O), 1590 cm⁻¹(C═O)

EXAMPLE 8Bis(3-N-cyclohexylamino-5,5-dimethyl-4,6-dioxocyclohexylidene)ethane

6 g of cyclohexylamine were dissolved in 40 ml of dioxane in thepresence of an amount of acetic acid sufficient to dissolve the saltintermediate. This mixture was added to a solution of 10 g of3,3,5-trimethyl cyclohex-5-ene-1,2,4-trione (from Example 2) in 40 ml ofdioxane. The mixture was left at room temperature for 45 minutes, in thecourse of which it turned reddish violet, and was then poured into 600ml of water with vigorous stirring. The precipitating platelets werefiltered off with suction and washed with a little methanol. The crudeproduct was purified by recrystallizing it once from dioxane and thendried in a desiccator.

Yield: 0.6 g (4% of theory), decomposition: 250° C. C₃₀ H₄₀ N₂ O₄M=492.7

Elemental analysis: calculated C 73.14; H 8.18; N 5.69; found C 72.98; H8.22; N 5.72.

¹ H-NMR₃₀₀ (d₁₈ -HMPT/TMS): δ=0.8-2.0 (bm; 20H, 2'-H, 3'-H, 4'-H, 5'-H,6'-H), 1.30 (s; 12H, Me₂), 3.40 (bs; 2H, 1'-H), 6.52, 7.08 (2×s; 2×2H,2-H, α-H), 10.60 (bs; 2H, NH)

In addition there are signals of further double bond isomers.

UV-Vis (dioxane): λ_(max) =536 nm

IR (solid, KBr): γ=3340 (NH), 2960 (CH₃), 2850 (CH₃), 1650 (C═O), 1580cm⁻¹ (C═C)

MS (70 eV): m/e (%)=492 (100, M⁺), 477 (11, M-Me), 462 (3, M-2 Me), 409(16, M-C₆ H₁₁), 246 (5, M/2)

EXAMPLE 9Bis(3-anilino-5,5=dimethyl™4,6-dioxocyclohex-2-enylidene)ethane

2.82 g of aniline and 5.1 g of trifluoroacetic acid were combined in 20ml of dioxane. This mixture was added to a solution of 5 g of3,3,5-trimethylcyclohex-5-ene-1,2,4-trione (from Example 2) in 20 ml ofdioxane. The batch rapidly turned reddish violet and was poured after 90minutes into 400 ml of water with vigorous stirring. The precipitatingproduct was filtered off with suction, washed with ethanol and ether andrecrystallized from 30 ml of boiling dioxane, giving darkish violet,metallically bright platelets.

Yield: 1.9 g (26% of theory), decomposition>300° C. C₃₀ H₂₈ N₂ O₄,M=480.6

Elemental analysis: calculated C 74.98; H 5.87 ; N 5.83; found C 75.24;H 5.65; N 5.86.

¹ H-NMR₃₀₀ (d₁₈ -HMPT/TMS): δ=1.35 (s; 12H, Me₂), 6.9-7.5 (m, 2-H, α-H),C₆ H₅)

UV-Vis (dioxane): λ_(max) =555 nm

UV-Vis (CHCl₃): λ_(max) =564 nm

UV-Vis (DMF): λ_(max) =572 nm

IR (solid, KBr): γ=3320 (NH), 2980 (CH₃), 1680 (C═O), 1650 (C═O), 1575cm⁻¹ (C═C).

The same method was used to obtain the dyes of the formula ##STR11##listed below in Table 1.

                  TABLE 1                                                         ______________________________________                                        Exam-                                  λ.sub.max                       ple                          Acid      [nm]                                   No.   R.sup.1      R.sup.2   (CHCl.sub.3)                                     ______________________________________                                        10    n-C.sub.4 H.sub.9                                                                          H         CH.sub.3 --COOH                                                                         540                                    11    --(CH.sub.2).sub.5 --                                                                            CH.sub.3 --COOH                                                                           552                                      12    p-Tolyl      H         CF.sub.3 --COOH                                                                         570                                    13    Naphth-1-yl  H         CF.sub.3 --COOH                                                                         582                                    14    CH.sub.2 --C.sub.6 H.sub.5                                                                 H         CF.sub.3 --COOH                                                                         548                                    15    n-C.sub.4 H.sub.9                                                                          CH.sub.3  CH.sub.3 --COOH                                                                         542                                    16    --CH.sub.2 --CH.sub.2 --O--CH.sub.2 --CH.sub.2 --                                                CH.sub.3 --COOH                                                                           550                                      17    CH.sub.2 --CH.sub.2 --C.sub.6 H.sub.5                                                      H         H--COOH   550                                    18    Cyclo-C.sub.5 H.sub.9                                                                      H         CH.sub.3 --COOCH                                                                        540                                    ______________________________________                                    

EXAMPLE 19Bis(1,1-dimethyl-2-oxo-5-phenyl-1,2,5-trihydrophenaz-3-enylidene)ethane

A solution of 3.3 g of N-phenylphenylene-1,2-diamine in 25 ml of dioxaneand 5 ml of trifluoroacetic acid was added to a solution of 3 g of3,3,5-trimethylcyclohex-5-ene-1,2,4-trione (from Example 2) in 35 ml ofdioxane. The batch, which turned bluish green, was left stirring at roomtemperature for a further hour, in the course of which the targetproduct already formed a substantial precipitate. After the suspensionhad been poured into 500 1 of water with intensive stirring, the greenprecipitate was filtered off with suction and washed with ethanol andether. Recrystallization from chlorobenzene gave the title product inthe form of greenish, metallically bright platelets.

Yield: 4.2 g (74% of theory), melting point: >280° C. C₄₂ H₃₄ N₄ O₂,M=626.75

Elemental analysis: calculated C 80.49; H 5.47; N 8.94; found C 80.62; H5.54; N 8.64.

UV-Vis (dioxane): λ_(max) =640, 328, 251 nm

UV-Vis (MeCONMe₂): λ_(max) =648 nm

IR (solid, KBr): γ=1670 (C═O), 1540 cm⁻¹ (C═N)

The same method was used to obtain the dyes of the formula ##STR12##listed below in Table 2.

                  TABLE 2                                                         ______________________________________                                        Example                                                                       No.           R.sup.1       R.sup.4                                           ______________________________________                                        20            C.sub.2 H.sub.5                                                                             H                                                 21            Cyclo-C.sub.6 H.sub.11                                                                      H                                                 22            CH.sub.2 --C.sub.6 H.sub.5                                                                  3-CH.sub.3                                        23            C.sub.6 H.sub.5                                                                             3-CH.sub.3 O                                      24            Cyclo-C.sub.6 H.sub.11                                                                      3-CH.sub.3 O                                      25            C.sub.6 H.sub.5                                                                             3-Cl                                              26            C.sub.2 H.sub.5                                                                             3-Cl                                              27            CH.sub.2 --C.sub.6 H.sub.5                                                                  4-CH.sub.3                                        28            C.sub.6 H.sub.5                                                                             4-CH.sub.3 O                                      29            cyclo-C.sub.6 H.sub.11                                                                      4-CH.sub.3 O                                      30            C.sub.6 H.sub.5                                                                             4-Cl                                              31            C.sub.6 H.sub.5                                                                             4-Cl                                              ______________________________________                                    

We claim:
 1. A cycloalkylidene dye of the formula I ##STR13## where m is0 or 1,L is a chemical bond or C₁ -C₂ -alkylene, which may bemonosubstituted or disubstituted by C₁ -C₄ -alkyl, R¹ is hydrogen, C₁-C₂₀ -alkyl, which may be phenyl-substituted, phenyl, phenyl substitutedwith C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or halogen, naphthyl or C₃ -C₇-cycloalkyl, Y is oxygen or two hydrogens, X¹ is oxygen and X² is C₁ -C₈alkanoyloxy, benzoyloxy, 2-methylbenzoyloxy, 2-methoxybenzoyloxy,2-chlorobenzoyloxy, C₁ -C₆ -trialkylsilyloxy or a radical of the formulaOR¹ or NR² R³, where R¹ is as defined above and R² and R³ are identicalor different and each is independently of the other C₁ -C₂₀ -alkyl,which may be phenyl-substituted, phenyl, phenyl substituted with C₁ -C₄-alkyl, C₁ -C₄ -alkoxy or halogen, naphthyl, or C₃ -C₇ -cyclalkyl or R²and R³ together with the nitrogen atom joining them may formpyrrolidino, piperidino, morpholino, piperazino or N-(C₁ -C₄-alkyl)piperazino, or else one of R² and R³ is hydrogen, or X¹ and X²together are a radical of the formula ##STR14## which ring systems mayeach additionally be monosubstituted or polysubstituted by C₁ -C₁₀-alkyl, C₁ -C₁₀ -alkoxy, nitro, amino, C₁ -C₄ -monoalkylamino, C₁ -C₄-dialkylamino, pyrrolidino, piperidino, morpholino, piperazino, N-(C₁-C₄ -alkyl) piperazino or halogen, where Z is oxygen, sulfur or NR²,where R² is as defined above.
 2. A cycloalkylidene dye as claimed inclaim 1, wherein L is a chemical bond or 2-propylidene.
 3. Acycloalkylidene dye as claimed in claim 1 of the formula II ##STR15##where R¹ is hydrogen, C₁ -C₁₀ -alkyl, which may be phenyl-substituted,phenyl or naphthyl andX² is as defined in claim
 1. 4. A cycloalkylidenedye as claimed in claim 1 of the formula III ##STR16## where n is 1, 2,3 or 4,R¹ is hydrogen, C₁ -C₁₀ -alkyl, which may be phenyl-substituted,phenyl or naphthyl and R⁴ is C₁ -C₁₀ -alkyl, C₁ -C₁₀ -alkoxy, nitro,amino, C₁ -C₄ -monoalkylamino, C₁ -C₄ -dialkylamino, pyrrolidino,piperidino, morpholino, piperazino, N-(C₁ -C₄ -alkyl)-piperazino orhalogen, and Z is as defined in claim 1.